Billy Ray Irick felt searing pain akin to torture before he died in a Tennessee prison in August, but steps taken before his execution blocked signs of suffering, according to a doctor who reviewed information about the lethal injection.

Dr. David Lubarskys statement is included in a new court filing entered late Thursday amid an ongoing legal challenge of Tennessee’s lethal injection protocol. He wrote that Irick “experienced the feeling of choking, drowning in his own fluids, suffocating, being buried alive, and the burning sensation caused by the injection of the potassium chloride.”

The documents also state Tennessee failed to follow its own protocol during Iricks execution, raising questions about whether executioners ever intended to ensure Irick was unable to feel the pain caused by the second and third lethal injection drugs.

Irick and 32 other death row inmates sued the state this year arguing that Tennessee’s new protocol for lethal injections would subject them to pain so intense it would violate the U.S. Constitution. They questioned the use of midazolam, the first of the three drugs the state administers during executions.

Lubarsky, a Florida doctor, testified for the inmates during a two-week trial in July. He said midazolam, which is supposed to render inmates unconscious and unable to feel pain, doesn’t work as intended. He said midazolam sedates inmates but does not stop them from feeling the effects of the other two drugs, vecuronium bromide and potassium chloride.

Lubarsky said statements from people who witnessed Iricks execution indicated the midazolam failed to ensure Irick could not feel pain during his death.

Lubarsky and other medical experts are the backbone for the inmates appeal. The case is not about whether the death penalty is constitutional, attorneys for the death row offenders wrote in the 390-word brief. Its about what the deadly drugs do to a body, and whether Tennessee citizens should approve of that likely tortuous outcome.

"This case is about whether it is constitutional to inject a human with a small bottle of acid – which will destroy the lining of their lungs and cause them to drown in blood – and then to inject them with a paralytic that will leave them conscious but expressionless – unable to speak or scream – feeling as if they are buried alive, and finally to stop their heart with an injection that will, in their last minute of life, cause them to chemically burn alive," wrote Kelley Henry and other federal public defenders working on behalf of the death row inmates.

Davidson County Chancery Court Judge Ellen Hobbs Lyle agreed Lubarsky and other experts were well qualified, but she rejected their arguments in ruling against the inmates.

Lyle said whatever pain the inmates felt did not last long enough to count as unconstitutional torture, a stance blasted by U.S. Supreme Court Justice Sonya Sotomayor in an opinion issued hours before Iricks death.

The remaining death row offenders continue to pursue their appeal of Lyles ruling even though no court stopped Iricks execution.

The Tennessee Department of Correction, represented by the Office of the Tennessee Attorney General, argued it is following the law and using drugs available to carry out the required punishment for death row offenders. Department officials noted during trial that the U.S. Supreme Court previously allowed executions using midazolam to proceed, arguing the usage is now case law.

In the latest filing though, Henry and the other attorneys argue that case law is not settled. They point to new and more expansive medical evidence, presented to Lyle during the trial, that has never been considered by the full Supreme Court.

They also blast the states arguments in the new filing, writing: "Defendants’ repeated mantra, barely acceptable from a teenager, is that – all the other states are doing it, so it must be ok."